Nigel Calder in the Times

As a prelude to a new book, Nigel Calder (who was the editor of New Scientist for four years in the 1960s) has written an op-ed for the Times (UK) basically recapitulating the hype over the Svensmark cosmic ray/climate experiments we reported on a couple of month ago (see Taking Cosmic Rays for a spin). At the time we pointed out that while the experiments were potentially of interest, they are a long way from actually demonstrating an influence of cosmic rays on the real world climate, and in no way justify the hyperbole that Svensmark and colleagues put into their press releases and more ‘popular’ pieces. Even if the evidence for solar forcing were legitimate, any bizarre calculus that takes evidence for solar forcing of climate as evidence against greenhouse gases for current climate change is simply wrong. Whether cosmic rays are correlated with climate or not, they have been regularly measured by the neutron monitor at Climax Station (Colorado) since 1953 and show no long term trend. No trend = no explanation for current changes.

Re #58: Charles, when I see results of the sort you quoted the first question I ask myself is whether the authors of the study have offered an opinion as to its significance. Since abstracts are often written with other people in the field in mind as the sole audience, often no such opinion is included. Fortunately, in the case you quoted the authors noted: “There is a need to understand and eliminate these solar irradiance inconsistencies in modeling (even though their overall impact is expected to be minor in comparison to impacts from inconsistencies introduced by the representation of clouds).” Bear in mind that there literally hundreds of papers published evey year with regard to needed improvements to the GCMs.

#56, even if there were cognitive dissonance, and somehow the whole AGW thing were overestimated or a farce, at least the error is in the right direction, bec the solutions to GW actually help the economy.

A lethally wrong direction error would be to assume AGW is not happening, when in deed it is happening.

So, if anyone can prove beyond a shadow of a doubt that AGW is not happening, then, well, I’ll still keep on reducing my GHGs, because it’s saving me money to do so & reducing many other harms, and, who knows, we may just need those fossil fuels when the earth starts in on a natural cooling cycle who-knows-when.

Re:98. So what do you think drives the muon production if it isn’t the GCR–in particularly the moderate to high energy portion above the magnetic cutoff?
As to your list of dissenting atmospheric scientists, shall we start with you naming 10 that regularly publish in relevant, peer-reviewed journals and seriously question the importance of anthropogenic mechanisms?
The UAH group has had to backtrack quite a bit on their satellite/balloon discrepancy. It is still nonzero, but MUCH smaller. I don’t think you can view this as a serious discrepancy at this point. Moreover, why should it surprise you so much that the insulator is at a lower temperature than the source of the IR.

RE #67 & 76, I know nothing about clouds & GW, but I think I read somewhere that some types of clouds lead to cooling and some to warming (I think the high whispy strat ones, or is it the other way around?).

Of course, that’s during the day when the sun is shining. I imagine at night, none of the clouds would contribute to further cooling, and it seems to me they all (to various degrees) might contribute to warming — the cloud “blanket-effect,” especially the ones that look like goose-down comforters. I guess I should eventually read some books on GW.

But I’m also interested in whether of not Cognitive Dissonance is having a greater impact on bias in AGW science than hard evidence. It is my firm belief that c.d. is the greatest single psychological factor responsible for unintended bias in scientific experimentation – partially because it is as prevalent in highly educated people as it is in the common man.”

I’d suggest people quit invoking “cognitive dissonance” when they mean something like “ignoring an inconvenient view”. Cognitive dissonance means nothing of the sort. Wikipedia has a decent summary:

Cognitive dissonance is a psychological term which describes the uncomfortable tension that comes from holding two conflicting thoughts at the same time. More precisely, it is the perception of incompatibility between two cognitions, where “cognition” is defined as any element of knowledge, including attitude, emotion, belief, or behavior.

When people carelessly use “cognitive dissonance” in discussions like this, they actually mean something like Piagetian assimilation. Assimilation is the process of altering or distorting perceptions of incoming stimuli in order to make the input fit into pre-existing cognitive schemata, while accommodation is the process of altering the schemata to take account of new data. Someone who systematically ignores contrary data illustrates the triumph of assimilation over accommodation, cognitive rigidity over learning.

I have a copy of Nigel Calder’s 1974 book The Weather Machine And The Threat Of Ice (BBC Books). It’s actually a good overview of the state of climate science at the time, even if it is a little sensationalist on the risks of an imminent ice age (10-1), and the suddenness of its onset (1 year).

I’m glad to see that Nigel’s still interested in climate issues, if still perhaps a little too attracted by the wackier end of the science.

So everybody that keeps pointing to neutron counts since 1953 or other measures in the last 30 years are using too short a timeline. Based on the sunspot number and beryllium-10 proxy, we have been flat since 1950. The increase happened from the late nineteenth century until 1950. The Sun is dramatically more active now and has been since 1950 than it was in the last several hundred years.

Jim Cross:
The sunspot numbers in your two links are from the work of Hoyt & Schatten. The same work has also been used to estimate climate forcings by the IPCC, and most climate modelers. See for example this graph from the TAR, which uses an earlier Hoyt & Schatten work.

re #103 [Tierny blog] I read through the comments there, a nice cross section of denialists, cranks and contrarians, with all the familiar canards trotted out. Under it all, woven into the bombast and protests and appeals to reason and Godliness and progress, you can sense the fear growing.

From such fear is many a fruitful action born. Let’s see what they do next.

As in any science, there is disagreement over the definitions of such conditions. Our argument is primarily one of semantics. Far be it from me to differ with Wikipedia, but a better definition may be to define cognitive dissonance as the discomfort felt at a discrepancy between what one already knows or believes and new information or interpretation. It occurs when there is a need to accommodate new ideas, and it may be necessary for the belief to evolve so that one may become open to new possibilities. I chose that specific psychological effect because of the similarities I see in the AGW community to the religious groups originally studied in development of the theory. (it was meant as an indirect dig at dhogaza after comment #50). But surely, you see the dissonance that would arise when beliefs developed by some researchers over 30 years of study are challenged by potent new ideas. We may want to believe that such dissonance does not bias our work, but research into the c.g. thoery suggests it is a prime motivator of even intelligent people.

It sort of occurred to me that Nigel Calder is not a denialist or contrarian or even a skeptic. His idea sort of reminds me of “cold, chemical fusion”….and interesting idea to throw in the ring, see if anything comes of it. Science into strange and new territories for the sake of science into strange and new territories. Stir up a rather slow digging, back-breaking science in the trenches.

The only problem is that while cold fusion would have been great (solving our GW problem!), this cosmic rays idea tends to detract from the serious need to shift focus from whether AGW is happening (which was settled enough for policy-makers back in 1990, & certainly by 1995) to actually doing something about it.

If it weren’t for the naysayers (including the policy folks) politicizing the issue and dragging their heels kicking & screaming, the cosmic ray idea might have even been fun.

In Reply to [Response: No trends in cloud cover are statistically significant given the uncertainties in the data and systematic issues with the satellite measurements. Why do you think there is an increase in ‘electroscavenging’? And what do you think is driving it?

The electroscavenging is modulated by changes in the ionosphere potential. (See item C from Brian Tinsley’s attached paper):

“There are at least three independent ways in which the solar wind modulates the flow of current density (Jz) in the global electric circuit. These are (A) changes in the Galactic Cosmic Rays (GCR), (B) changes in the precipation of relativistic electrons from the magnetosphere, and (C) changes in the ionospheric potential distribution in the polar caps due to magnetosphere-ionosphere coupling. The current density (Jz) flow between the ionosphere and the surface, and as … “(Tinsley follows with a desciption of the electroscavenging process which collects cloud ions, causing rain, and inhibiting or reducing the formation of clouds.)

The changes in the ionosphere potential is due to re-occurring solar coronal holes. From the attached paper “The decreasing correlation between sunspot number and geomagnetic activity, and the deviation of global temperature trend from solar activity as expressed by sunspot index are due to the increased number of high-speed streams of solar wind on the decreasing phase and in the minimum of sunspot cycle in the last decades.”

[Response: We AGW types can take an accurately observed trend in a physical quantity (the CO2), relate it via careful laboratory measurements to a well-characterized physical process (infrared absorption), embed that process in a range of models extending from the simplest Arrhenius type models to Manabe-Strickler radiative-convective models, to full GCM’s, and out of the latter get a curve of not only temperature but patterns in space and time which agree in most important respects with the observations. We can relate predicted physical consequences to the energy imbalance of the ocean, and then go out in data and see the effects on ocean heat storage much as predicted. When GCR types can do half that, and also explain why infrared absorption plus decline of temperature with height should fail to yield the predicted warming, I’ll start to take the idea seriously. I’m still waiting to see trends in anything related to GCR that could even have a prayer of giving the recent temperature pattern, and I’m still waiting to see a first-principles derivation of the magnitude and distribution of radiative forcing purportedly due to GCR. Then there’s also the matter of the lack of a climate signal associated with the Laschamp magnetic excursion. –raypierre]

Of course everyone seems to have conveniently forgotten that back in July/August California was experiencing a record-setting heat wave, and until last weekend the Sierra snowpack was as low as I can remember seeing at this time of year. Now weren’t those climate models predicting an increase in weather extremes?

Re #118: “But surely, you see the dissonance that would arise when beliefs developed by some researchers over 30 years of study are challenged by potent new ideas.”

What potent new ideas? The one under discussion seems more like dredging the bottom of the barrel for something, anything, that will let its supporters go on refusing to accept responsibility for the consequences of their actions. As for beliefs… Climate science can build models using known physics, put observed data into them, compare the results to what is actually happening in the world, and find that the models are a good match for the real world. Seems like there’s precious little room for belief in that process.

So for any of you that want to put forth competing models, why not follow the same process? There are, I think, several GCMs that have publicly-available source code. (Perhaps the RC folks have links handy?) Take one of those, modify it if needed to use your theory as well, run it, and see how well it does.

This ought to be fairly easy for the “the sun got brighter years ago, but stopped as soon as we started doing satellite measurements” theory. As mentioned earlier, the models allow varied insolation inputs. Put yours in, tell us what comes out. You might even publish a paper or two :-)

“Response: So what is the positive evidence that muon flux has changed in recent decades? It’s not sufficient to assert that it might have done and so there might be an unquantified effect on climate. Occam’s razor starts to come into play here…. – gavin”

There are two bits of evidence. One, that it would be possible to draw a statistically justifiable line with a slight down slope through the muon flux data that we have. I cited Svensmark’s graph of data from 1937-94, which could be continued forward. Only a small trend down in flux would be needed.

Second, I cited the various studies finding an approximate doubling in solar coronal magnetic field strength in the past 100 years or so. It’s not unreasonable to assume that, if a valid observation all or in part, this phenomenon would reduce GCR flux in general & muons in particular.

Of course I’d like much more evidence, but this is enough in my opinion to deem GCR effect on nebulosity at least a plausible explanation for any global warming that might have occurred over the past century.

The evidentiary situation is similar to that for the greenhouse effect. Indeed, the CGR hypothesis would appear prima facie to have the stronger case. AGW advocates point to the coincidence between some global warming & an increase in CO2 & other greenhouse gases, & feel they know the mechanism whereby these gases have warmed the earth. Yet there are important problems, such as the fact that the atmosphere has apparently warmed less & later than the surface, contrary to what greenhouse theory would predict. Also, the planet has been warmer at previous times in this interglacial period & during all previous interglacials of which we have record, without benefit of elevated CO2.

Atmospheric scientists haven’t come up with a natural explanation for current warming, so turn to an anthropogenic cause for global warming. Skeptics say we’re just coming out of another natural cold spell in the usual interglacial cycle of warmer & cooler periods, that current warmth is nothing special & doesn’t particularly need explanation any more than the Holocene Climatic Optimum, Roman or the Medieval Warm Periods.

The correlation between climate on earth & sunspots is suggestive, just as is CO2, but presently lacking in the hard data you or I would like to see to support the hypothesis. I would also like to see more physical data supporting the greenhouse effect & fewer reruns of computer simulations testing new & scarier proposed feedback mechanisms.

In fact, I’d like to spend more atmospheric & climatic research funds on muon telescopes & less on redundant (to me) GCM runs, unless maybe they attempt to model cloudiness. Not that I have anything against GCM models. I like those for the Last Glacial Maximum, for instance. I feel they work better at millennial & centennial time frames than for decades & years. Finer resolution requires data of higher reliability, which are largely lacking. But more significantly, they lack predictive power, while any number of questionable adjustments can make them match past data.

Few if any theories are without problems. The history of science is replete both with problematic theories that are now objectively, undeniable true & with consensuses invalidated by once anathematized hypotheses. In my opinion, both explanations for climate change forcings are plausible.

[Response: Changes in the IMF should modulate all GCR – as you state above. Therefore, since there is no trend in the best observed GCRs (i.e CLIMAX), that would seem to go against the idea that muon fluxes are also changing. Let me be clear – I’m not saying that muon fluxes are unchanged nor that they can’t effect climate – both things could be possible – but this idea really has some significant problems. And given that CLIMAX was taken as a proxy for GCR by Svensmark originally – I find it odd that this is now dismissed as being irrelevant. More fundamentally, we haven’t come up with GHG induced warming because of lack of other options, it is because the physical consequences of increasing GHGs actually match the obs without much trouble. – gavin]

Re #113 (Jim Cross): There’s a pretty poor correlation between that cycle and the behavior of climate during the Little Ice Age. If the sunspots are really confirmed by the Be10 proxy and really do correlate with solar radiance changes that in turn have such a substantial impact on climate, there should have been a very sharp climate excursion globally between 1650 and 1750, with the temperature increase between 1700 and 1750 constituting the bulk of the increase between 1700 and the present. As well, warming should have leveled off after 1950, but instead it went through a slight cooling followed by a very rapid warming. This all becomes hard to reconcile. As well, any climate scientist (really, any meteorologist) could tell you that it’s very easy to imagine all sorts of false correlations based on a fragment of a cycle such as the one you point to.

Re #118 (Edward Barkley): “But surely, you see the dissonance that would arise when beliefs developed by some researchers over 30 years of study are challenged by potent new ideas.” Actually I could, but in this case the evidence would seem to indicate that I don’t need to. See this from Rabett Run:

“Department of there is nothing new under the sun:

“Reviews of Geophys. and Space. Sci. 16 (1978) 400

“Dickson [1975] suggested that solar related fluctuations in some aspect of cloudiness may connect solar activity to the meteorology of the lower atmosphere. He thought that this connection might occur via the effect of cosmic ray induced ionization on aerosol and cloud condensation nuclei and thus on the radiative properties of clouds. p403

“Dickinson Bull Am Meteorol. Soc 56 (1975) 1240.

“Somewhat better than Nigel Calder and the Revenge of the Killer Cosmic Rays.”

“Re:98. So what do you think drives the muon production if it isn’t the GCR–in particularly the moderate to high energy portion above the magnetic cutoff?”

Muons are a form of GCR, modulated by the sun’s IMF. I questioned whether neutron counted at or below the surface are directly proportional to muons in the troposphere. A look at the graph I cited with data from 1937 to 1994 in the case of muons, compared with neutron flux, shows the difference. I also linked a discussion from SLAC about muon production & their effect on cloud formation. I myself don’t know all the factors that produce different patterns in the record of these & other forms of GCR, or whether particle & astrophysicists feel they do. It should suffice to know that there is a difference.

Ray also commented: “The UAH group has had to backtrack quite a bit on their satellite/balloon discrepancy. It is still nonzero, but MUCH smaller. I don’t think you can view this as a serious discrepancy at this point. Moreover, why should it surprise you so much that the insulator is at a lower temperature than the source of the IR.”

As you know, I commented that adjustments to the satellite & balloon data that now show warming, however less & later than the surface. The data don’t surprise me. The point is that they fly in the face of greenhouse theory prediction, & not just any prediction, but the one most essential to the hypothesis, reradiation of energy absorbed by the gases in the lower atmosphere. We can differ as to the seriousness of this discrepancy, but to me it seems critical. In my opinion, it’s not a trivial outlier to the theory, as was say Mercury’s orbit to Newtonian gravity, latter explained by Einstein.

Ray continued, “As to your list of dissenting atmospheric scientists, shall we start with you naming 10 that regularly publish in relevant, peer-reviewed journals and seriously question the importance of anthropogenic mechanisms?”

The peer review process for many relevant journals has become part of the problem in the AGW discussion. Many skeptics are retired, so no longer subject to retaliation for heretical departures from AGW orthodoxy. Thus I’m not sure that regularly publishing need be a criterion, if they’ve done so with distinction in the past, but I’ll comply with a ? after names that you might not find acceptable.

For purposes of this discussion, I hope you’ll agree that the consensus view is that global warming in at least the last century is real, that it’s primarily attributed to human activity, which has increased greenhouse gases in our atmosphere via the greenhouse effect, that this warming will continue & get worse through positive feedbacks, leading to consequences ranging from negative to catastrophic by 2100. Opinions differ as to whether it’s too late or not to do anything to avert calamity, although suggestions to ameliorate the consequences previously considered bizarre are now worth considering.

Many if not most AGW skeptics believe that humans have some effect on climate change. By “primarily”, I mean at least more than half of the warming is attributable to human activity, & probably much more, with possibly as little as 10% from natural cycles. Again consensus scientists have wiggle room to quibble on this point.

By this definition, I don’t know to what extent satellite data collectors & analyzers John Christy & Roy Spencer, would still consider themselves AGW skeptics, since I’ve never read how much climate change either scientist now feels is natural & how much man-made. Christy recently wa quoted, “part of what has happened over the last 50 years has clearly been caused by humans.” Is “part” more or less than half?

[edit]

[Response: John, you are doing fine with the discussion of specific issues, but this isn’t the forum for cutting and pasting irrelevant lists of names. Please stick to the scientific points of dispute. – gavin]

So is the jury still out on the Suns activity being partly responsible for the current warming, not responsible at all or not responsible since the AGW signal arose from the natural background of the current climate?

How much additional output would the Sun need to exhibit to warm the atmosphere by the 0.6 – 0.8 C that we are currently experiencing and is there any evidence of it?

I would suggest that climate scientists have looked at the Sun in as much depth as is currently available to the from NASA/ESA and the like. How can anyone now say that the Sun is SOLELY to blame?

I don’t see your LIA argument at all. There is a significant increase in Be-10 during the time you mention which would be associated with reduced solar activity.

As for the 1950s and after, the leveling of Be-10 and increased warmth can be reconciled by several factors. First, remember the leveling is already at a much higher level of solar activity than the previous several hundred years. Second, there is probably some lag time involved. Third, the Sun is not the only factor. Yes, GHG is a factor (I don’t deny that) and maybe global dimming.

It seems to me that the offical RC position is that the Sun is certainly a factor but just not a significant one in current warming. An extreme denialist position is the warming is caused wholly by the Sun. I am closer to the official RC position but believe we may be underestimating the effects of solar activity.

Thank you Lynn Vincentnathan /107 this is what I thought.
Svensmark proposes that lower solar activity results in more cosmic rays penetrating the atmosphere, resulting in more cloud formation resulting in lower temperatures.
Clouds act as a blanket keeping the heat in!
Perhaps he should clarify this point.

I think PK has hit the nail on the head. There is too much
> accusatory and alarmist rhetoric in the whole
> debate. It would be nice to
> see an independent, or at least, philosophically
> balanced panel take a look
> at all of the evidence and come up with an unanimous
> decision on the state
> of the Global Warming debate at this time.
>
> The IPCC simply has too many deficiences from both a
> scientific, and a
> political standpoint to be the independent voice of
> reason in this debate.

[[You probably know reputable atmospheric scientists who would not agree that AGW is a perfectly good model & that there are credible competing hypotheses, if not personally, then through their work. I do.]]

I know of reputable astrophysicists who still don’t buy the Big Bang. But they’re a tiny minority, just like the AGW deniers. Scientific consensus isn’t an arbitrary thing; it goes with the evidence. The deniers haven’t got a leg to stand on.

[[Re BPL (82). I suppose if scientific truth was based on a vote, you’d win. [edit – no politics]. The ridiculed minority are not necessarily wrong. That’s why its important to carefully assess the facts and feel the need to be convinced ‘yourself’ rather than to go with your heart, the flow, the popular view, etc. ]]

Your assumption that that’s where I get my information is unwarranted, pal. I got into radiation physics when I started writing radiative-convective models of planetary atmospheres. How many have you written?

It would be nice to see an independent, or at least, philosophically balanced panel take a look at all of the evidence and come up with an unanimous decision on the state of the Global Warming debate at this time.

The IPCC simply has too many deficiences from both a scientific, and a political standpoint to be the independent voice of reason in this debate.

This is one of the reasons climate scientists sometimes get a bit “riled up.” The IPCC is exactly what was asked for: an objective, scientific evaluation of all the evidence. The conclusion they have reached doesn’t satisfy the non-believers, so they have resorted to calling it “political” and even unscientific.

Every objection to AGW has been given serious consideration. When it is found wanting, the nonbelievers cry foul.

I keep hearing this line. AGW deniers have “new ideas” which the stodgy establishment ought to listen to.

Heads up. The impossibility of global warming was standard doctrine from about 1900-1950, with a few brave exceptions like Hulbert and Callendar in the ’30s. AGW IS the new idea. More importantly, it has the evidence behind it.

It isn’t whether an idea is new or old, brave or timid, progressive or reactionary, that matters. It is simply and solely whether it is true or false.

[[The evidentiary situation is similar to that for the greenhouse effect. Indeed, the CGR hypothesis would appear prima facie to have the stronger case.]]

From the rest of your post, I see you apparently don’t believe in the greenhouse effect, let alone AGW. May I ask what you think keeps the Earth from freezing over? Its emission temperature with the present albedo is 255 K, you know. Water freezes at 273 K.

[[The data don’t surprise me. The point is that they fly in the face of greenhouse theory prediction, & not just any prediction, but the one most essential to the hypothesis, reradiation of energy absorbed by the gases in the lower atmosphere.]]

The idea that greenhouse gases don’t absorb and radiate energy (they don’t “reradiate” it) has been so massively proved by so many experiments that it really does constitute pseudoscience to deny it. And again, I ask you, if the greenhouse effect doesn’t work, what keeps the Earth from freezing over? Want the math to demonstrate that it would be frozen over if not for the atmosphere’s greenhouse effect? I promise not to use anything tougher than algebra.

[[Svensmark proposes that lower solar activity results in more cosmic rays penetrating the atmosphere, resulting in more cloud formation resulting in lower temperatures.
Clouds act as a blanket keeping the heat in!
Perhaps he should clarify this point. ]]

Clouds are strong greenhouse agents, but they are also highly reflective (at least the ones low down are). On average the cooling from high albedo dominates over the heating from the greenhouse effect, though just slightly (I believe I’ve seen the figure 20 W/m^2).

Re #98: You say “What matters is muon flux in the lower atmosphere, more than overall flux in space.” I’m having a good bit of trouble seeing why this should be so. Why should muons be the _only_ species that affects clouds, and not all the other charged particles zipping around?

As I understand it, the premise of the GCR theory is that charged particles cause ionization which causes clouds to form. We know this mechanism works in the lab, since the cloud chambers used as early particle detectors used a variation on it, but I don’t see how it can discriminate among particle types. As long as it has a charge, it leaves a track.

So why the claim that only muons have an effect on natural cloud formation?

Re 126 “Muons are a form of GCR, modulated by the sun’s IMF.”
Nice try. Muons are relatively longlived leptons that form from the weak decays of hadrons produced by the GCR. Trends in muons should follow GCR, since GCR is ultimately the driving force.

As to the UAH results, given that they have had to revise them, what, 3 times now, and always in the direction of decreasing discrepancy, I would question how well they understand their dataset. No shame there–as anyone who has tried to parse a multi-satellite dataset would know.
Your assertion that climate skeptics face persecution would be laughable if it were not so common. I know of no scientist who has suffered financially for denying climate change–most have been remunerated very well. The stiffest sanction I know of for a contrarian in any scientific field was that they weren’t allowed to teach their opinions as fact in graduate and undergraduate courses. Now a scientist in the pay of an organization actively trying to disseminate disinformation and subvert the scientific process–that’s a different situation entirely. They would indeed be ostracized for turning their back on the rules of scientific inquiry–not for disbelief in any specific scientic theory.

c) Regardless of how much or little we know about past climate variation, we can be pretty darned sure it wasn’t caused by a sudden increase in CO2 due to burning large amounts of fossil fuels, because that’s never happened beforem and so in that sense discussion of past variation is irrelevant.

Besides, you’re asking the question backwards. Climate scientists aren’t invoking human-produced CO2 to explain warming, they’re predicting that increasing CO2 produces warming. Suppose for instance we’d had fast computers and the necessary theory & data back in the mid-1800s: the climate scientists of the day could have come up with the same models, and used them to predict the warming that a given CO2 increase would cause, long before the increase or the consequent warming had started.

From Calders op-ed:
“The sunâ��s magnetic field bats away many of the cosmic rays, and its intensification during the 20th century meant fewer cosmic rays, fewer clouds, and a warmer world. On the other hand the Little Ice Age was chilly because the lazy sun let in more cosmic rays, leaving the world cloudier and gloomier.”

I am not sure if this is in the original paper or it is just Calder’s interpretation but to me it presents a problem. That is the assumption that more clouds = cooler world and less clouds = warmer world.

Now this would only be true if the cosmic rays produced high altitude cirrus clouds that perhaps reflect more energy straight back into space than they trap long wave radiation from the Earth. Then less reflecting clouds means warming as more radiation is hitting the Earth. However if cosmic rays produce more low altitude darker clouds then these would trap more long wave radiation than reflect short wave radiation so in this case less clouds would mean cooling because there are less clouds so less long wave radiation is trapped.

To my mind then even if the ideas presented in this paper are absolutely true there is no real way of knowing what the effect could be. I cannot think of an experiment that would nail the types of clouds that cosmic rays form more of. It may even be that the cosmic rays create equal amounts of both leading to no net effect which seems to be the observation that there is no correlation.

I want to try these questions again because I am trying to sort out as a layman how to evaluate the CRF vs. GHG debate. Can someone explain to me how increased CO2 (which I assume is fairly well measured over a long period) is correlated to observed temperature increase? Is it as simple as a theoretical projection being compared to observations?

How is this balanced against claims that CRF (or GCR) may also be significantly responsible for the warming we are seeing? Is there a change in the last 50 yeaers of solar activity, that supports saying GCR increase can explain a significant portion of the current warming rate?

From what I have read around, the implementation of these models on computers is very complex and requires corrective routines to deal with numerical error. Are these programs open sourced for auditing?

Please feel free to rip to shreds any mistaken thinking I am using to phrase these questions, I am here to learn. Also, I know there are a lot of good debate archived at this site, so if a pointer is all it takes, please provide it.

Thank you Fabien Bulabois for alluding to the fact that Nigel Calder’s comments in the Sunday Times do not reflect New Scientist’s views on climate change. Nigel Calder was editor of New Scientist from 1962 to 1966. He has written twice for New Scientist since 1997 (which is as far back as I can go in our online archive), and his views are entirely his own.

“None of this means that we can stop worrying about global warming caused by emissions into the atmosphere. “The temperature of the Earth in the past few decades does not correlate with solar activity at all,” Solanki says. He estimates that solar activity is responsible for only 30 per cent, at most, of the warming since 1970. The rest must be the result of man-made greenhouse gases, and a crash in solar activity won’t do anything to get rid of them.
[…]
“There is a dangerous flip side to this coin. If global warming does slow down or partially reverse with a sunspot crash, industrial polluters and reluctant nations could use it as a justification for turning their backs on pollution controls altogether, making matters worse in the long run.”

In light of the IPCC’s fourth assessment report, Solanski’s estimate of solar radiative forcing was generous. The IPCC’s figures were cited in our coverage of the Paris release earlier this month.

That paper’s description of CO2 contribution tracks far better than the current IPCC estimates, and leaves CO2, at best, as a minor contribution to the variation in Global temperature.

[Response: You make a good point, different timescales must be treated differently, and then you blow it by suggesting that correlations over the hundred million year timescale have relevance to the last few decades (even assuming that their analysis was valid, which I would not- see http://pubs.giss.nasa.gov/abstracts/2004/Rahmstorf_etal.html ). -gavin]

Meanwhile, in “bizarre calculus land” we’re still waiting for a single icecore showing carbon dioxide rise preceding temperature rise, rather than the other way around. You know, where cause precedes effect aka “Reality”.

[Response: Possibly the concept of feedback doesn’t exist in your world? You, know, where one thing leads to another which leads back again…. Or maybe you have found a way to deduce a causation purely from a correlation. Do please let us know…. -gavin]

Heh. The Contrarians and Denialists sure have stepped up the “our minority opinion is being repressed and therefore must be right!” rhetoric since the SPM came out. Spluttering and bombast, heat and smoke and very little light. Shortly they will have to either crawl off to vent their spleens in private chat rooms filled with others of the Michael Savage/Crichton/tinfoil hat crowd, or else change their tune to even have a place at the table with the grown ups. Must make for a hard choice.

Firstly, i’m no expert. I want people to steer my thought, so here’s a brain dump, please correct me where you see fit.

I don’t believe we can totally discount the effects of the sun on global warming. After all there is a near 100% correlation between heating by the sun and the temperature here on earth (imagine how warm our planet would be without the sun).

My issue with all current mainstream (if there is such a thing) thinking on global warming is that it relies almost completely on retention of heat from the sun by greenhouse gases, and kind of assumes that solar effects are constant, which clearly they are not, even if they do not present a trend.

I’m no expert, (as you’ve probably already gathered), but one thing I do know from my limited science education is that physical systems are extremely complex. I just find the whole idea that global warming is just down to one effect (the greenhouse) difficult to believe.

In the scheme of things the levels of change we are experiencing while extreme for earth, are tiny on a universal scale, and with such complex systems can we confidently say that we’re right?

As for your CSI analogy (lead story today), well I kind of disagree with your sentiment. It only works if you assume that each ‘event’ is unrelated, but in fact how can they be unrelated, they are a product of the same extremely complex environmental systems, even if the mode of ‘event’ is different. Again I just see this as over simplification, how do we know for example, that one of the previous ‘event’ triggers isn’t having an influence on temperature now (no matter how subtle). Not all crimes are commited by one person or with the same motive. How about combining CSI and Cold Case?